Collections in museums usually have boxes of specimens which remain ‘undiscovered’ and yet which may be of importance or interest. The recent rediscovery of specimens of Archaeocidaris in the Nationaal Natuurhistorisch Museum, Leiden, from the Carboniferous of Egypt illustrates this point. These specimens were collected in 1938 by Dr. H.M.E. Schürmann (1891-1979), who had been a student of Professor J. Wanner (1878-1956), the noted expert on fossil echinoderms. The Egyptian Archaeocidaris plates include interambulacrals and radioles. These are closest to Archaeocidaris rossica (von Buch) from the Moscow area of Russia, although there are sufficient differences in radiole morphology to suggest that they are not necessarily conspecific.